1. Field Of The Invention
This invention relates to cathode ray tube bases, and more particularly to a connective-protective adapter for use with a CRT base to provide both connector pin protection and versatile electrical connective means for the tube.
2. Background Art
In cathode ray tubes of the type commonly utilized in television and allied display applications, most external electrical connections are made through a plurality of connective pins or leads traversing and extending outwardly from the neck closure of the tube. These pins are usually spacedly oriented in an annular array surrounding the sealed exhaust tubulation of the tube.
During tube processing and subsequent tube utilization, large potential differentials, in the order of many kilovolts, are applied between certain of the connector pins. Thus, it is common practice to incorporate arc protective means into the tube bases temporarily utilized in tube processing and also into those bases applied to the finished tubes.
It is also essential that connector pin alignment be maintained to facilitate efficient base application and socket insertion. Any bend in a pin or pins, however slight, significantly increases insertion force, and may even prevent basing or socketing. To promote straightness, individual pin enclosure means, such as pin-accommodating bores formed in temporary pin protective means have been used, as for example, those taught in U.S. Pat. Nos. 4,158,152; 4,273,400; and 4,152,040. Other protective means for maintaining pin straightness have also been incorporated into base structures. For instance, a plurality of open longitudinal channels or grooves formed in the base structure support the individual leads while enabling side electrical contact with them. Such a structure, as disclosed in U.S. Pat. Nos. 3,979,157 and 4,040,708, also provides alleviation of inter-pin arcing.
To insure straightness and electrical isolation of a specific high voltage pin such as the focus lead from the other pins, a silo-type base has been developed. As disclosed in U.S. Pat. No. 4,345,812, the silo is a tubular structure formed as an integral part of the base.
Such base structures are designed to mate with conventional sockets in equipment such as TV chassis, and are thus affixed to the finished tubes. Prior to affixing of such final base, however one or more processing bases are applied to the tube at certain manufacturing stations, for instance to provide the high voltage focus lead with an external connection for electrical processing. CRT processing is a multi-step procedure initially involving heating of the gun structure, conditioning of the thermionic cathodes, and exhausting of internal gasses. Subsequent to the sealing of the exhaust tubulation, the tube is conditioned by application of discrete potentials to specific tube electrode elements to electrically stabilize the tube and minimize the possibilities of inter-electrode arcing. To achieve this desired electrical conditioning, temporary bases and other connective means are conventionally utilized. The application and removal of the temporary processing bases and the ultimate affixation of the final permanent base represent appreciable time and cost considerations in tube manufacturing.